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Thread: 2019 Mustang GT incredible MAF row axis

  1. #1
    Advanced Tuner Auto-Hentzschel's Avatar
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    2019 Mustang GT incredible MAF row axis

    Today I tried to tune a 2019 Mustang GT with JLT CAI. Simply thing normally. This time I tried to use the factory row axis from the [ECM] 44317 - MAF Airflow vs. Period. Did some other adjustments in spark and torque section to get a good result. Butt on every pull I got IPC wheel torque error and the torque wrench comes up. I go back to stock step by step, still IPC wheel torque error. Again and again. Finally I fixed that error with a different row axis for the MAF airflow table. Added back all power adjustments and the car rund perfect and add some serious numbers. Can someone explain why the scale of the row axis can produce IPC wheel torque error?
    The MAF curve was not perfect, but it was not more than 5-10% fuel trim error. In any case not enough to get this error.
    MAF_bad.jpgMAF_good.jpg
    EVO2++_IPC Error.hpl

  2. #2
    Advanced Tuner CCS86's Avatar
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    Just look at the shape of the curve in your "bad" photo. It's terrible.

    It isn't necessarily just the axis values, but the combination of the axis values and the table values made for a very jagged function.

    MAF transfer functions should be very smooth curves.

  3. #3
    Advanced Tuner Auto-Hentzschel's Avatar
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    Quote Originally Posted by CCS86 View Post
    Just look at the shape of the curve in your "bad" photo. It's terrible.
    I know, the curve need to be smooth. But this is not the error. It is not bad enough for PCM Pail Mode. Always if I collect Data for the MAF curve, it fails. Only the different row data fixed it.

  4. #4
    Advanced Tuner veeefour's Avatar
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    3rd Gen Coyte is extremely sensitive to MAF changes - car might not even run at all. Something different in that new Bosch ECU compared to old Siemens/Continental.

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    Quote Originally Posted by Auto-Hentzschel View Post
    I know, the curve need to be smooth. But this is not the error. It is not bad enough for PCM Pail Mode. Always if I collect Data for the MAF curve, it fails. Only the different row data fixed it.
    Hm, silly question, but have you adjusted the period-rows/scale to be logged for the '19 in your Scanner-Tool too? Maybe they are mismatching.
    Last edited by nonnex; 1 Week Ago at 07:51 AM.

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    take stock maf curve and multiply by 1.50 then use the stft error to fine tune it.

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    Advanced Tuner Auto-Hentzschel's Avatar
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    how it looks, someone do misunderstand my post. I don't need a explanation how to tune a MAF curve. I only will show you, that a incorrect MAF row axis on the new Mustang GT PCM get wheel torque error and fail safe errors.

  8. #8
    Advanced Tuner CCS86's Avatar
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    I still don't really understand your confusion. You fed the PCM a garbage MAF function and it complained. That doesn't surprise me.

    You didn't even post up what the actual error was. You just said "...the torque wrench comes up", which I'm assuming means you got a check engine light; and there would be associated trouble codes with that.

  9. #9
    Advanced Tuner Montecarlodrag's Avatar
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    I had similar issues yesterday. 2019 manual with a C&L CAI
    My MAF curve is very smooth but it needed from -10 to -15% adjustment on the upper cells. AFR in OL follows commanded with less than 1% error.
    However the car is acting weird. As soon as it's started a dash error comes "Hill Start assist not available", then a wrench error that says "Check owner manual". When those errors are present the Sport, Track modes can't be selected. Downshift RPM matching is also disabled. No IPC Wheel Torque errors so far.

    With HPT scanner I found no DTCs however I tried a SCT X4 and found P086E (Neutral Position sensor A Circuit intermitent/Erratic) and P095B which has no description, the only page that has it listed has this description: "ISO/SAE Reserved"

    If I flash the stock tune those issues go away. I haven't found the solution yet.

    Best Regards.
    Attached Images Attached Images
    10 sec Montecarlo SS

  10. #10
    Advanced Tuner Auto-Hentzschel's Avatar
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    Quote Originally Posted by CCS86 View Post
    I still don't really understand your confusion. You fed the PCM a garbage MAF function and it complained. That doesn't surprise me.

    You didn't even post up what the actual error was. You just said "...the torque wrench comes up", which I'm assuming means you got a check engine light; and there would be associated trouble codes with that.
    no engine light, no DTC! only fail save mode and torque wrench.
    I just fixed it with custom row axis for the MAF curve. every thing works good and engine runs fine.

  11. #11
    Advanced Tuner veeefour's Avatar
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    Quote Originally Posted by Auto-Hentzschel View Post
    no engine light, no DTC! only fail save mode and torque wrench.
    I just fixed it with custom row axis for the MAF curve. every thing works good and engine runs fine.
    This is what you should do if you don't have any bench flow data provided for given CAI.

    It takes time to do it right tho - I like to stick with CAI's that comes with flow bench data like JLT or PMAS.